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Pest Spotlight: Picture-winged Fly
1 Jul, 2008 By: Gerry Wegner Ph.D. Pest Management ProfessionalDelphinia picta (Diptera: Ulidiidæ)
The picture-winged flies of the Family Ulidiidae (formerly Otitidae) are represented by about 127 species in North America. The common name ascribed to the flies in this family refers to the black and yellow patterns on the otherwise transparent wings. Delphinia picta is the picture-winged fly species most often encountered in urban and suburban settings in the eastern half of the United States.
 Gerry Wegner |
Adults of this species measure ¼- to 1/3-in. in length. The head is rust-colored. The thorax is rust and gray, and the abdomen is brownish-black. The front of the head and mouthparts extend forward like a military gas mask.
In the South, D. picta sometimes is confused with true fruit flies of the Family Tephritidae. In addition, customers often misidentify and describe picture-winged flies as "flying ants" when reporting their activity to pest management professionals (PMPs). As a result, PMPs may be called upon by homeowners to control the so-called "flying ants" on their premises.
 IPM Measures |
D. picta adult population that may be quite abundant — reaching nuisance pest status — on porches, patios and decks of residences and commercial buildings. They favor structures surrounded by trees, especially crabapple and other fruit-bearing trees, as well as shrubs and other ornamentals.
The flies themselves are harmless, but they display a peculiar wing-waving/flagging behavior while at rest on surfaces.
 Picture-winged Fly |
BIOLOGY
Mated female picture-winged flies lay their eggs (400 – 500 per female) on dead and decaying plant material, including ripe, decaying fruit, decomposing vegetables, bulbs, roots and foliage. The saprophagous larvae (maggots) feed as they tunnel through the moist rotting plant tissues and surrounding soil.
 Apple Maggot Fly |
This species is multivoltine – capable of several generations per year, climate permitting. Development from egg, through 3 larval instars and pupation requires 36 – 53 days in locations and during seasons characterized by warm to moderate temperatures. In northern climates, winter is passed in the soil as final (3rd) instar larvae.
In early May the overwintered larvae break diapause and migrate to the soil surface to form puparia.
Adults emerge in late May. Under ideal conditions, adults (particularly longer-lived females) can live for up to two months.
Wegner is the technical director and staff entomologist of Varment Guard Environmental Services in Columbus, Ohio. You can reach him at 614-794-8169 or e-mail
gerry.wegner@varmentguard.com.
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